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Animal Health
Tuesday, May 24, 2016 1:26:08 PM
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A primer: swine health issues in China - current status and management strategies

 

By An Ming LI, DVM


 

 

The period from April 2014 to May 2015 was one of the lowest points in China's swine market in recent history. In April 2014, losses of nearly 350 renminbi per head were seen. Continuous losses were witnessed throughout the period which was also one of the longest in record.

 

Even when prices breached the 16-renminbi-per-kilogram mark in July 2015, restocking levels of sows were nowhere as high as those seen in 2007 and 2011, and this is expected to have a profound impact on swine supply in 2016.

 

Separately, for the past two years, the Chinese government has been stepping up its efforts in controlling environmental pollution, forcibly shutting down farms with obsolete equipment and excess emissions. Approval for land use and from their environmental impact assessments has been especially difficult. This is particularly so for farms in the more economically developed regions with dense populations such as the Pearl River Delta and Yangtze River Delta.

 

With local farm production and slaughter rates declining in these regions, and pork consumption staying strong, swine prices for 2016 are expected to be far above their breakeven points but below their historical highs. Slaughter prices for Duroc/Landrace/Yorkshire breeds are expected to be kept at 15 to 17 renminbi per kilogram for the rest of 2016. As the prices of the two major feed ingredients — corn and soymeal — are trending lower, farm profit per head is expected to remain at 500 renminbi or more, until the end of 2016.

 

However, high swine prices and profitability for farms may be hiding deep-seated problems in swine health. The disease situation for swine has not changed significantly, and the level of feed management remains low. According to available statistics, average litter size is a mere 15.9 head per sow, a far cry from the 25 head per sow levels seen in Denmark and the United States.

 

For the past two years, while there were no large-scale swine epidemics in China, health, pollution and drug residue issues on farms remain serious. Disease is still the topmost issue affecting farm production levels, and the following diseases are the main threats or potential threats to the Chinese swine industry. 

 

Viral diseases

 

The prevention and control of classical swine fever has been a top priority for swine farms, and China probably has among the world's best vaccines for classical swine fever. With appropriate measures in place, there have been no recent outbreaks of the disease, and its management could be said to be very successful.

 

For Porcine Reproductive and Respiratory Syndrome (PRRS), currently there are rarely serious outbreaks of the disease, which is probably a result of the widespread use of its vaccine. However, most farms are still testing positive for the virus, and the concern of the development of more virulent strains of the virus from viral variation and reassortment, is the key reason why are some farms are still reluctant to use the PRRS vaccine. Consequently, whether one should or should not use the vaccine, has often been a topic of debate. With the plethora of vaccines for different variants from local and foreign manufacturers, together with the lack of investigation into the specific variant on farm, farms tend to 'blindly' administer vaccination. Of course, this means that the effectiveness of vaccination will then be uncertain, and it is precisely this lack of a standard for vaccine evaluation, which remains a problem. In addition, the destructive effects of PRRS on the swine immune system easily lead to secondary infections such as porcine circovirus type 2 infection, polyserositis and polyarthritis.

 

In the past three to four years, pseudorabies, another viral disease important to the Chinese swine industry, has seen a resurgence. Since the 1990s, the widespread use of the gene-deleted K61 vaccine had apparently effectively controlled the disease. However, cases which have occurred since October 2011 seem to indicate that the vaccine may not be fully effective and that the disease is making a comeback. The main symptoms include miscarriage in sows, rapid death in newborn piglets, significant respiratory problems in medium to large pigs, and often secondary infections by Actinobacillus and Pasteurella bacteria. There are two key areas in the future study of pseudorabies: one, the emergence of new viral variants; two, the lack of adequate protection from vaccination for pigs which have underlying PRRS infection.

 

For the winter to spring season, porcine epidemic diarrhoea (PED) often manifests itself in newborn piglets, resulting in huge losses. The effect of vaccines is often not conclusive, and the use of medicated feed has also not been very effective. Improving temperature and humidity levels in swine housing can sometimes significantly reduce morbidity and mortality rates, but again this is not conclusive. PED often occurs concurrently with infectious gastroenteritis and rotavirus infection, further increasing the difficulty in diagnosis and prevention. In short, PED remains a difficult problem for the Chinese swine industry.

 

Bacterial diseases

 

Mycoplasmal pneumonia tops the list of swine bacterial diseases, with a widespread presence on most farms. For farms where housing facilities are kept in good condition, and feed safety management is at a high level, symptoms are mild, otherwise they can become serious. The impact of this disease is persistent and huge for farms, and while it may be ideal for breeder farms to commercial farms to be thoroughly disinfected, this may be difficult to achieve. Promoting the use of vaccines may significantly reduce clinical signs of the disease.

 

Incidences of swine erysipelas, atrophic rhinitis, polyserositis, polyarthritis, Streptococcus suis infection and other bacterial diseases are often sporadic, with the effect of antibiotic treatment being significant.

 

Antibiotic use in the Chinese swine industry

 

However, the persistent use of antibiotics has been resulting in the development of antibiotic-resistant strains, and this poses a rising risk to the Chinese swine industry. The difficulty in standardising antibiotic use on farm continues to be a problem, due to a lack of awareness and poor facilities on most farms.

 

The main antibiotics used are Tiamulin, Doxycycline, Tilmicosin, Florfenicol, cephalosporins, aminoglycosides, penicillins, and quinolones. For foreign brands, prices are higher but it is generally believed that quality assurance is greater. It is said that customer service and product communication provided by local small to medium drug companies are generally better than those provided by foreign drug companies. With many local brands in the market, quality levels are heterogeneous. As some local drug companies are focussing on building their brands, they are steadily raising their quality levels, committing to technological and product innovation, and leading market trends in China's antibiotic market. Recognising the strengths in technical service which local small to medium drug companies possess, many small to medium farms are working with them because their own levels of technical expertise are low. Rising internet use among small to medium farms is expected to increase opportunities for remote services, and it would do good for drug companies to provide them suitable products and services through such a medium.

 

Industrial farms with an annual slaughter capacity of 500 to 10,000 head is currently the norm for the Chinese swine industry. Pollution from such farms and their excessive use of antibiotics are increasingly of concern for the Chinese government. This is particularly so as social concern relating to food safety issues such as drug residues in meat is rising. The three-pronged approach taken by the government is unprecedented: the elimination of backward farms; the standardisation of the production process; and, the strengthening of the inspection of meat products.

 

"Green farming" - some recommendations

 

Firstly, it is important to control the housing environment, especially in terms of temperature and humidity levels, which if well managed, could raise productivity levels. The importance of good ventilation should also not be neglected, which reduces both the airborne pathogen count and concentration of ammonia, which could greatly reduce swine susceptibility to infection.

 

Secondly, the illegal adding of antibiotics to feed should be prohibited, thereby ensuring that pigs respond well to antibiotics, and that there will be no antibiotic residues in pig meat.

 

Thirdly, tight biosecurity and disinfection on farm is probably the most effective means of disease prevention in swine production, stopping pathogens from even getting near the pig. This is particularly relevant to high-density, intensive farming, where fast growth of swine is required, naturally resulting in reduced immunity in swine. For example, for swine with reduced immunity from PRRS infection, the importance of appropriate biosecurity measures cannot be overemphasised.

 

Fourthly, vaccine use should be expanded. For example, although the use of PRRS vaccine is still controversial, with the effect of the vaccine reported as unsatisfactory at times, swine susceptibility to the disease is very high in the Chinese housing environment, and vaccine use is still probably the most effective preventive measure.

 

Fifthly, some animal health companies have developed probiotic products which reportedly improve the intestinal flora and provide viable nutrients, thus increasing swine immunity and reducing the reliance on antibiotics.

 

China's swine production capacity is massive, with an annual slaughter rate of over 500 million head. Disease issues will continue to be the bottleneck in the continued development of the country's swine industry. Swine diseases are becoming more atypical, and often occur concurrently, increasing the difficulty in their prevention and control. Regardless of the difficulties, China's environmental policies look set to tighten, and food safety issues are coming to the fore. With antibiotic-free "green farming" becoming the trend, focussing on the prevention and control of pathogens, and swine herd health, must be the direction of future work for the veterinarian in China.
 
 
For more of the article, please click here.

Article made possible through the contribution of An Ming LI, DVM
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